• Korean Chemical Engineering Research
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• v.52 no.5
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• pp.564-573
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• 2014

Economic optimization of cumene manufacturing process to produce cumene from benzene and propylene was studied. The chosen objective function was the operational profit per year that subtracted capital cost, utility cost, and reactants cost from product revenue and other benefit. The number of design variables of the optimization are 6. Matlab connected to and controlled Unisim Design to calculate operational profit with the given design variables. As the first step of the optimization, design variable points was sampled and operational profit was calculated by using Unisim Design. By using the sampled data, the estimation model to calculate the operational profit was constructed, and the optimization was performed on the estimation model. This study compared second order polynomial and support vector regression as the estimation method. As the sampling method, central composite design was compared with Hammersley sequence sampling. The optimization results showed that support vector regression and Hammersley sequence sampling were superior than second order polynomial and central composite design, respectively. The optimized operational profit was 17.96 MM$ per year, which was 12% higher than 16.04 MM$ of base case.

• 전기의세계
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• v.36 no.9
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• pp.658-664
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• 1987

최적이득을 구하는 해석적인 방식으로 안정여유에 의한 최적화방식과 공액경사법에 의한 최적화방식을 살펴보았으며, 두방식을 비교해 보면 몇몇 문제점이 존재하나 다음의 몇가지 점에서 공액경사법에 의한 최적화방식이 더 우수하다는 것을 알 수 있다. 1) 제어루우프내의 제어기 수에 관계없이 이 방식을 쉽게 적용할 수 있다. 2) 시스템을 수식으로 모델링할 때 거의 간략화함이 없이 표현하므로 실제 시스템과의 오차를 줄일 수 있다. 3) 평가함수 내의 가중치를 조정하여 원하는 과도응답을 가지는 최적이득으로 유도할 수 있다. 공액경사법에 의한 최적화방식은 벡터제어나 전류제어PWM등 보다 복잡한 제어루우프에도 쉽게 적용시킬 수 있으며 직류기 및 서보전동기의 속도 및 위치 제어시스템에도 적용이 가능하다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.9
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• pp.31-38
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• 2009

In this paper, we propose new gain optimization method for Sigma-Delta A/D converters. First, in proposed method, the 10 candidates are selected through SNR maximization for Sigma-Delta modulator. After then, it is shown that optimum gains can be obtained through MSE calculation for CIC decimation filter. In the simulation, The proposed method has advantages which utilize SNR maximization for modulator and MSE minimization for CIC decimation later. The more candidates are chosen in SNR maximization for modulator, the better gains can be obtained in MSE minimization for CIC decimation filter.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.61-67
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• 2008

To design flight control law of an unmanned aerial vehicle, automated control gain determination program was developed. The procedure for determination of control gain was formulated as the control gains were designed from the optimal solutions of the optimization problem. PSO algorithm, which is one of the evolutionary computation method, and SQP algorithm, which is one of the nonlinear programming method, are used as optimization problem solver. Thru this technique, computation time required for finding the optimal solution is decreased to 1/5 of that of PSO algorithm and more accurate optimal solution is obtained.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.05b
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• pp.5-9
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• 2003

장주기 격자 필터를 이용한 EDFA용 이득평탄화 필터 설계에는 대역폭에 따라 한 개에서 세 개까지의 평탄화가 가능하다 이러한 필터 설계는 EDFA의 고유의 중심 파장, 크기, 대역폭에 대한 각 장주기 광섬유 격자의 중심 파장, 크기, 대역폭을 설정하여 이득평탄화를 최적화시킨다. 이득평탄화 필터의 설계를 위한 방법으로써 수동 설계통한 이득평탄화를 했으나, 신속하고 편리함을 위해 반자동 설계, 자동 설계 프로그램을 구현하였다. 이를 통한 이득평탄화 정도는, 수동이 0.38dB, 반자동 0.57dB, 자동 0.62dB 정도로 정밀한 이득평탄화를 얻을 수 있는 설계가 가능하였다.

• Proceedings of the Korea Contents Association Conference
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• 2014.11a
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• pp.45-46
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• 2014

금속 격자 배열 안테나의 이득을 최적화하려면 격자배열 원소의 개구면 깊이를 조정하여 위치에 관계없이 동위상 특성을 이루도록 해야 한다. 각 개구면의 깊이가 안테나 이득에 미치는 영향은 서로 종속적이어서 결정론적인 방법으로 풀기는 쉽지 않다. 본 논문에서는 기존의 Armijo 법칙을 적용한 방향 탐색 기법을 제안한다. 실험결과 방향 탐색 기법은 금속 배열 안테나 최적화 문제에서 효율적인 것을 확인하였다.

• Journal of Korea Multimedia Society
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• v.6 no.7
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• pp.1159-1168
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• 2003

In this paper, a new wavelet filter design algorithm is proposed which optimizes energy compaction of transformed coefficients. The filter, designed by the proposed algorithm enhances the coding gain of the system with fixed quantizer by most unevenly distributed energy in transform domain. The coding gain function was extended to obtain the optimal filter coefficients in each stage. The experiments showed that the filter designed by proposed method outperforms conventional filters in energy compaction rate.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.268-270
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• 2013

본 논문에서는 최근 주파수 자원에 대한 수요가 급증하면서 효율적으로 주파수를 이용하기 위해 주파수 공유를 하면서 생길 수 있는 비용문제의 최고의 이득을 발생시킬 수 있도록 하기 위하여 이종네크워크(Heterogeneous Network)에서 매크로셀과 펨토셀 환경에서 스펙트럼 공유에 있어서 매크로셀이 사용하지 않는 스펙트럼을 펨토셀에 공유해줌으로써 이득을 취할 수 있는데 이러한 이득에 있어서 최고의 이득을 발생시킬 수 있도록 하기 위하여 펨토셀의 스펙트럼 공유당 비용 최적화 알고리즘을 제안 하였다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.4
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• pp.1-8
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• 2010

In this paper, we propose a new gain optimization technique for Sigma-Delta A/D converters. In the proposed scheme, multiple gain set candidates showing maximum SNR in the modulator block are selected, and then multiple gain set candidates are investigated for minimum MSE in decimation block. Through CIC decimation filter simulation, it is shown that second SNR ranking candidate in modulation block is the best gain set.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.38 no.2
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• pp.16-26
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• 2001

This paper develops the fast dynamic programming technique to construct the subband structure yielding the maximum coding gain for given filter bases and a given limit of implementation complexity. We first derive the unified coding gain which can be applied to non-orthogonal filter basis as well as orthogonal filter basis and to arbitrary subband decompositions. Then, we verify that the unified coding gains in real systems are monotonically increasing function for the implementation complexities which are proportional to the number of subbands. By using this phenomenon, the implementation complexity and the coding gain are treated in the same way as the rate and distortion function. This makes it possible to use the Lagrangian multiplier method for finding the optimal subband decomposition producing the maximum coding gain [or a given limit of implementation complexity.